"People in this country are crying out for a Conservative Party that is decent, reasonable, sensible, common sense and in it for the long term of this country and that is the party we are going to build," he said.

Mr Cameron said there was still a "vast mountain to climb" but the Tories could return to government.

He set out core challenges for his leadership: creating a full-bodied economic policy which went beyond just tax; giving freedom to those on the frontline in public services; national and international security; and ensuring social justice by strengthening the voluntary sector.

Labour was not capable of meeting those challenges, he claimed.

"They are yesterday's men with yesterday's measures," added Mr Cameron.